As the presidential campaign shifts from the Republican primary fights to a general election matchup between President Barack Obama and former Massachusetts Gov. Mitt Romney, a new study by the Pew Research centre’s Project for Excellence in Journalism shows that the president’s media coverage in 2012 has been consistently negative while his Republican challenger has experienced a more mixed narrative.

Obama’s negative coverage exceeded positive coverage in 14 of 15 weeks studied, while positive coverage outweighed negative for Romney in six of the 15 weeks and was fairly evenly divided in four more.

The likely cause of this? A number of factors, most prominently the Republican primary season and the media repeating their candidates’ attacks on Obama. Also, Pew cites a “tenuous” economy, the unfavorability of the health care law as it was challenged in the Supreme Court, the still-high unemployment rate, and an early-year surge in gas prices.